xfs: add DAX block zeroing support
Add initial support for DAX block zeroing operations to XFS. DAX
cannot use buffered IO through the page cache for zeroing, nor do we
need to issue IO for uncached block zeroing. In both cases, we can
simply call out to the dax block zeroing function.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index a52bbd3..4a29655 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1133,14 +1133,29 @@
break;
ASSERT(imap.br_blockcount >= 1);
ASSERT(imap.br_startoff == offset_fsb);
+ ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
+
+ if (imap.br_startblock == HOLESTARTBLOCK ||
+ imap.br_state == XFS_EXT_UNWRITTEN) {
+ /* skip the entire extent */
+ lastoffset = XFS_FSB_TO_B(mp, imap.br_startoff +
+ imap.br_blockcount) - 1;
+ continue;
+ }
+
lastoffset = XFS_FSB_TO_B(mp, imap.br_startoff + 1) - 1;
if (lastoffset > endoff)
lastoffset = endoff;
- if (imap.br_startblock == HOLESTARTBLOCK)
+
+ /* DAX can just zero the backing device directly */
+ if (IS_DAX(VFS_I(ip))) {
+ error = dax_zero_page_range(VFS_I(ip), offset,
+ lastoffset - offset + 1,
+ xfs_get_blocks_direct);
+ if (error)
+ return error;
continue;
- ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
- if (imap.br_state == XFS_EXT_UNWRITTEN)
- continue;
+ }
error = xfs_buf_read_uncached(XFS_IS_REALTIME_INODE(ip) ?
mp->m_rtdev_targp : mp->m_ddev_targp,